This glowing green shell belongs to a species of "clusterwink snail" that lives in the ocean. Its special molecular composition makes it the perfect material to filter light. Already, scientists are thinking about ways to manufacture it for this purpose.

The snail that lives inside this shell has the power to glow, and it illuminates as a defense mechanism when predators are near - possibly to make itself appear larger. Though its shell appears a dull, opaque yellow in ordinary light, it's actually made of a heretofore unknown material that's precisely tuned to disperse the exact wavelength of light the snails are emitting. The shell becomes almost transparent when the green bioluminescence streams through it.

If engineers can artificially reproduce the material in this shell, we could conceivably have tinted windows, sunglasses, or optical instruments designed only to let one color of light through.

A release about the unusual physical properties of this clusterwink snail explains:

Discovering how the snail spreads its light came as a surprise to the researchers since this species of clusterwink features opaque, yellowish shells that would seem to stifle light transmission. But in fact when the snail produces green bioluminescence from its body, the shell acts as a mechanism to specifically disperse only that particular color of light.

The opaque shells of clusterwink snails would seem to blunt light transmission. [Dimitri] Deheyn says such adaptations are of keen interest in optics and bioengineering research and development industries.

"The light diffusion capacity we see with this snail is much greater than comparative reference material," said Deheyn, of Scripps' Marine Biology Research Division. "Our next focus is to understand what makes the shell have this capacity and that could be important for building materials with better optical performance."

Want to get a tan in the dark? Now you can take in some ultraviolet rays without all that pesky visible light, using a modified version of the clusterwink shell.